What should I do ? Honest opinion about it please ...

Basically ...what happened was that before my anniversary with my boyfriend I cheated .... I am not that type of person I swear ..what happened was that I was at the dog park and I saw this dog and thought why not go see it and touch him and I asked permission ... me and the guy we started asking questions like how old the dog and breed and how many dogs etc ... it was just short talks here and there ...and he ended up bringing up that he was going to Give away 3 of his dogs I believe and I asked if they were girls or guys and he said that he had one that was a girl but she’s pregnant and after she gives birth he will give her away.... -and i asked him that I wanted a girl for on of my dogs because I want his bloodline to keep going and I needed a female dog ... and he said sure and that it was crazy how I accepted right away even though I haven’t seen the dog so he asked for my number and I said sure just to send the pictures... and at around 8ish he sent me the pictures and I said if that was the dog etc and I was like okay we getting her ..and than we ended up talking a little bit more about school work and life in general and than I just said that I am Gaona leave becaue i don’t want to bother besides I wasn’t feeling well and he said that we could talk if I wanted to becaue he going through stuff too..I than said it’s okay that I am fine and that we will talk another time about the dog ...and he said if we could just take a ride to wawa and talk and honestly I needed someone to talk about it and get out of the house becaue run always so stuck woth my thought and I end up crying all night for my relationship ... therefore I accepted ...we went it for a ride and I went to the back seat and he was driving becaue i wanted to be respectful... we than ended up talking about life and how we are feeling ... I ended up telling him that I had this complicated relationship and that I love my boyfriend more than anything and that’s why I stayed with him because I want to work out with him ... he gave me advice for it and we ended up going to a parking lot where his ex lived and started talking about his ex and I gave him advice too for that ... and than we ended up being in silent and just thinking and having our own thoughts ...I mentioned to him that I wished it was my boyfriend here because I would be cuddling with him and holding g hands and having long talks woth smiles and laughs..and like I said we ended up being in silent and just thinking and he said he got tired and that he wanted to go to the back seat and I was like okay you can go ... and he did ...before that he gave me head scratches out of nowhere and I was like ..... -.... but u didn’t say anything and jokingly I wasn’t even being serious I told him that if he wants I can give him a headscratch too...and he said yes but I was just kidding and I just did it and told him it would be fast ... and I went to the backseat because he wouldn’t move a little forward to the front ...and he ended up pulling me towards him to give him a. Hug /cuddle ...and I was just awkward knowing that I had a bf and that I couldn’t do this but I needed a hug and I accepted it ..and he got a little too closer where I told him I had a boyfriend and that this is not good and he said it’s just a one time thing and that he wasn’t trying to do anything ..he than pulls my chin to kiss him and I said no ..Becaue I had a boyfriend and I can’t do this I love him ....and he said that he wasn’t pulling me to kiss him ... he than got really close again and idk what happened but we kissed for like 3 seconds before I backed off and broke down crying knowing I cheated ... and I hate myself to this moment that I did that ... and idk what will help me to move on ..I told my boyfriend and he was shocked that I did because I am not the type of person to do that... and he’s upset with me which us understandable... what do I do now? What do you think he should do ? I just want honest opinions from both perspectives ...I honestly just want to know how you guys feel about it ....